Fugitive-staining process for textile fibers

ABSTRACT

A fugitive-staining process for distinguishing two different textile materials, particularly but not necessarily, basicdyeable polyester fibers from unmodified disperse-dyeable polyester fibers. In one of its preferred forms the process comprises testing fabrics in which basic-dyeable and dispersedyeable polyester yarns, with or without other types of textile fibers, e.g. nylon or wool, are patterned for cross-dyed effects or in which one yarn is a suspected contaminant in the other. The fabric is wet with a solution of a moderately high-boiling ester in a volatile diluent, treated with an aqueous or alcoholic solution of an acidic dye or optical brightening agent, and usually heated to develop a color contrast. The basic-dyeable yarn develops a deeper stain which is easily removed by scouring.

Bino

[4 June 25, 1974 FUGITIVE-STAINING PROCESS FOR TEXTILE FIBERS [75]- Inventor: Charles F. Bino, Greensboro, NC.

[73] Assignee: Burlington Industries, Inc.,

Greensboro, NC.

[22] Filed: Aug. 9, 1972 [21] Appl. No.: 279,058

Related US. Application Data [63] Continuation-impart of S'er. No. 177,858, Sept. 3,

1971, abandoned.

521 US. Cl. 8/164, 8/21 c [51] Int. Cl. D06p 3/00, D06p 3/54 [58] Field of Search 8/164, 21 C, 168

[56] References Cited UNITED STATES PATENTS 2,222,798 11/1940 Ellis et al. 8/164 2,298,432 10/1942 Thompson 8/164 2,959,461 11/1960 Murray 8/164 Primary ExaminerThomas J. Herbert, Jr. Attorney,

Cushman 5 7] ABSTRACT in which one yarn is a suspected contaminant in the other. The fabric is wet with a solution of a moder- V ately high-boiling ester in a volatile-diluent, treated with an aqueous or alcoholic solution of an acidic dye or optical brightening agent, and usually heated to develop a color contrast, The basic-dyeable yarn develops a deeper stain which is easily removed by scouring.

28 Claims, No Drawings Agent, or Firm-Cushman, Darby, &

1 FUGITIVE-STAINING PROCESS FOR TEXTILE FIBERS CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of application Ser. No. 177,858 of Sept. 3, 1971 now abandoned.

BACKGROUND OF THE INVENTION This invention concerns the fugitive staining or tinting of fibers, yarns, and fabrics, in particular those comprised wholly or in part of polyesters.

In the manufacture of fabrics it is frequently desirable to combine two or more different kinds of yarns into sometimes intricate plied, blended, woven, knitted, tufted, needled, non-woven, etc., patterns. One may, for instance, achieve interesting cross-dyed effects by using various combinations of dye-receptive and dye-resistant yarns in conjunction with one or more dyes or dyeings.

Other more completely physical needs, such as processability, tensile or elongation properties, wearability, and the like may lead one to work with plied yarns or patterned structures. Even in the simplest of combinations, the possibility exists of making plying, weaving, or knitting, etc-., errors that may go undetected until final dyeing.

It is accordingly highly desirable, at various stages in I the patterning of two or more yarns, to be able to confirm quickly and reliably that the intended fiber is being or has been used, and that the desired pattern has been uniformly achieved. Several methods can be used to reach this objective. One is to color the entire original lot of each fiber or yarn component with a differentcolored fugitive stain or tint and, after completing the yarn blend or fabric construction and confirming its structural integrity, to scour the color away. This method affords absolute control, but it is expensive because it involves advance staining of all or at least one of the component fiber lots or yarns, followed by later scouring of the entire fabric output. A more serious fault of this form of art tinting is the weakness of the shades it affords. Pastel shades are conventional, for if enough tint is added to give deep colors, it can cause crocking and other troubles in subsequent processing.

The pastel shades can hardly be used at all for random mixture detection, for here the weak colors become too diluted for the eye to see.

Numerous variations based on the principle of the foregoing method may be found in the art. One example is the process of US. Pat. No. 2,959,461, which depends upon (I) combining selected dyes with certain water-soluble and dye-substantive polymers such as poly-N-vinylpyrrolidone, (2) colorcoding each of the utilized fibers by staining with one of these combinations, (3) forming a fabric, and (4) subsequently scouring away the dyed polymers after they have served their purpose.

Another known controlmethod, essentially a sampling technique, consists of completing the fabric and then removing suitable swatches for test dyeings', before committing all toa final dyeing. This method leaves most of the fabric untested, inherently has a much lower order of reliability, and involves the destruction of the test samples.

It is not only in the deliberate use of more than one type of fiber at a time that a reliable, quick, and fabricsaving identification test can be of great value. For example, in the creeling of warp yarns it is not uncommon for as little as a single bobbin of a foreign yarn to be come incorporated in the warp supply and go undetected until a misdyed thread or other fault appears in the final fabric. This is particularly true when a mill is simultaneously using, or even merely storing, more than one type of fiber, polyester in the present instance, which happens with ever-increasing frequency in the present state of the art. Early detection of a bobbin of basic-dyeable polyester accidentally included on a creel supposedly loaded with only standardpolyester, or vice versa, has great cost-saving potential.

For the fibers to which it is applicable, the present invention solves most of the aforementioned problems of the art. In particular it permits the operator, at his option, to choose any degree of uniformity testing between the extremes of total tintingand spot checking, andto make his choice at any stage where routine quality control or suspicion of an error suggests that a test should be applied. 1

SUMMARY OF THE INVENTION In its broadest aspect, the invention contemplates a fugitive staining process for distinguishing between two or more differently colorable textile components by treating the same with an ester and an aqueous or alcoholic solution of a fugitive coloring agent which differentially stains the components so that the components can be suitably identified. The coloring agent may thereafter be removed from the components by scouring or equivalent means.

Although certain other combinations of fibers may also be detected, the present invention primarily comprises a process or distinguishing between standard disperse-dyeable and basicor cationic-dyeable polyester yarns, either standing separate from each other or combined in blended or plied yarns, or in patterned or mispatterned fabrics. In a typical and generally preferred procedure the invention comprises treating a fabric, designed for development of a patterned dyeing based on the differential dye-substantivities of the two types of fibers, with a solution of an at least moderately highboiling ester in a volatile preferably substantially waterimmiscible inert solvent, further treating with an aqueous or alcoholic solution of an acidic dye, and then usually heating to bring out a color contrast in the yarns present. A remarkable and wholly unexpected discovcry of the invention is that it is the basic-dyeable yarn in the combination which is preferentially colored by the acidic dye. When properly applied the color is fugitive and easily scoured from the fabric after the test has accomplished its purpose. Furthermore, when such as the hereinafter described selected combinations of esters and dyes are used, differentiation of the polyesters in the presence of other fibers may be achieved without loss of fugitivity.

The process may also be applied to yarn threadlines or coned yarns.

DETAILED DESCRIPTION The surprising discovery which underlies the present invention-is that the presence of an ester causes an acidic dye or its equivalent to be preferentially attracted to a basic-dyeable polyester fiber. I know of nothing in the art to suggest that this should be so.

The invention comprises a fugitive-staining process which is primarily concerned with distinguishing basicdyeable from disperse-dyeable polyester textile products by treating them, separately or together, and optionally in the presence of other fibers, with an ester and an aqueous or alcoholic solution of a dye which preferentially stains the basic-dyeable fibers in said products.

A wide variety of esters have been found-effective. They may be applied either alone or in the presence of a volatile inert, preferably substantially waterimmiscible organic diluent. An ester, in the context of this invention, may be a mixture of two or more esters.

The preferred dyes are acidic, the term being inclusive of both the widely used acid dyes of the art and of certain other dyes which, although they carry acidic groups, are trade-designated by other class names, as described further hereinafter. The acidic dyes may be in either their free-acid or water soluble salt form. Certain optical brighteners may also be used effectively. I have found a few other water soluble dyes which, despite the apparent absence of acidic groups, perform like the acid dyes in this invention. Basic dyes, although they too are preferentially attracted to the basicdyeable polyester fibers, are not fugitive and therefore are excluded.

More specifically, with certain exceptions detailed hereinafter, the process usually preferably comprises the steps of treating yarns or fabrics containing members of either or both of the class of disperse-dyeable and basic-dyeable polyester fibers with a solution of an ester in a volatile preferably substantially waterimmiscible organic diluent, further treating with an aqueous solution of a preferably acidic or anionic dye and usually heating to develop a color contrast in the fibers, i.e., a deeper color in the basic-dyeable than in the disperse-dyeable fibers, the process being effective and the color being fugitive on the polyester fibers in either the presence or absence of other kinds of fibers. The order of treatment with ester and dye may be varied, i.e., the dye may be applied first, or the solutions may be sprayed simultaneously from a dual or mixer nozzle. The further conventional step of scouring is usually applied to remove the color from the fibers.

The invention provides a process for complete fugitivity of stain on multicomponent yarns and fabrics containing disperse-dyeable polyesters, basic-dyeable polyesters, and other fibers limited only by the degree of fugitivity of the stain on the other fibers. Thus, as shown in the examples which follow, proper choice of dyestuff and ester makes it possible to distinguish the two types of polyester in the presence of fibers such as wool, rayon, acetate, or nylon.

The invention is primarily concerned with distinguishing between disperse-dyeable and basic-dyeable polyester fibers, but it is believed that the inventive principle may also be applicable to other kinds and combinations of fibers, such as nylons, acetates, rayon, wool and acrylics, even in the absence of one or both types of polyesters.

Although smaller structural units, i.e., individual fibers, may be distinguished by application of suitable optical devices to overcome the unfavorable effects of magnification on color depth, the invention primarily has utility on units large enough to be examined by the naked eye, i.e., bulk fiber, and filament, and yarns and fabrics. Thus, the invention is more applicable to differentiation of aggregates of the same fiber, as, for example, in incompletely dispersed carded fiber blends, than of fully separated and blended individual fibers. The yarns may, however, themselves be mixtures. For example, a yarn comprising a 65-35 blend of rayon and disperse-dyeable polyester may be distinguished by the process of the invention from a yarn comprising a 65-35 blend of rayon and basic-dyeable polyester. In the context of this invention the word yarn denotes a structure large enough to be examined without magnification, the invention being largely discussed and exemplified in these terms. The yarns may be in the form of either threadlines, cones, or fabrics.

Ordinarily, unless it has distinguishing characteristics such as a difference in denier or texture, a bobbin or other supply package of basicor cationic-dyeable polyester yarn such as described in U.S. Pat. No. 3,018,272 is essentially indistinguishable, before dyeing, from a similar-shaped bobbin of conventional disperse-dyeable polyester. Typical commercially available basic-dyeable polyester fibers are Types 62, 64, and 92 Dacron (DuPont); Types 402, 404, and 764 Fortrel (Fiber Industries); Type 541 Kodel (Eastman); and Type 440 Trevira (Hystron). These are believed, in general, to be copolymeric types, deriving their basic-dyeability from the presence of sulfonic groups in their molecules.

A large variety of disperse-dyeable polyesters, the best known of which is polyethylene terephthalate, U.S. Pat. No. 2,465,319, are commercially available. Among the other disperse-dyeable homopolymeric and copolymeric polyesters falling within the scope of this invention are those described in U.S. Pat. Nos. 2,901,466, 3,056,761, 3,288,755, 3,291,778, and 3,299,171 and British Pat. No. 1,093,377. Types 54 and 56 Dacron are used in the examples as representatives of this class.

Under the simplest conditions where the textile products under test are composed solely of disperse-dyeable polyester and basic-dyeable polyester, either separate or together, a wide range of choice of esters, dyes, solvents, and operating conditions, as disclosed in more detail hereinafter, is available. Greater selectivity becomes important, however, when additional fibers, such as nylon, cotton, wool, acetate, rayon, and others, are present. The process obviously depends, if complete stain fugitivity is desired, upon the complete release of tint by all of the component fibers on scouring; in such circumstances there should be no additional fiber present which is substantive to and permanently stained by the dye employed under the test conditions. One skilled in the art, using the teaching of this invention, will find that separations specific to more complex mixtures of yarns can be handled with ease. One may, for instance, detect and distinguish all three yarns in a fabric containing disperse-dyeable polyester, basic dyeable polyester, and nylon 66 or nylon 6, without loss of fugitivity. Component yarns in even more complex mixtures may be differentiated if the various shade contrasts developed are sufficient. It even appears that if the dyeabilities of different lots of the basic-dyeable polyester vary significantly, this variance can be detected by the method of this invention. it is believed that the polyesters may also be detected in the presence of cotton, but here the problem of permanent staining seems to be more difficult to control.

The mechanics of the invention are simple. For example, in a generally preferred sequence of steps, fabrated, leaving behind a pattern or streaks where the basic-dyeable fiber 'carries the predominance of color and the disperse-dyeable fiber carries almost none. Conventional scouring easily removes the color. Blue dyes are in general preferred over yellows and reds because the shade contrasts they produce are more strik- At times it may be preferable to reverse the order of application of the ester and dye solutions. For example,

in a test where the object was to confirm the composition of a cone of yarn, best differentiation was achieved by first spraying the end (essentially the cross-section) of the cone with dye, and then painting on the ester solution. The yarns had been deliberately wound onto the cone in units such that the cross-section presented a series of lightand dark-colored bands after application of dye, ester, and heat.

Although here the observed contrast is not so pronounced as in fabrics and yarn packages, the test may also be applied effectively to individual threadlines, either isolated or collectively, as in the warp supply from a creel. A narrow band of ester solution is painted across the open warp, dye solution is applied over it, and heat is used to develop a uniform color, a patterned. sequence of two different shades of color, or one or more randomly mismatched variations, depending upon whether it is a single-fiber warp, a patterned twofiber warp, or an accidentally contaminated or misaligned war p. A simple scour laterremoves the band of color.

Distinguishing between the yarns does not depend upon their being in direct contact. Even if separate yarns, bobbins, or fabrics of the two types of polyesters are tested, the darker color develops on the basicdyeable fiber. The color contrast seems, however, to be less pronounced when there is no opportunity for migration of dye solution from disperse-dyeable to basicdyeable fiber.

Fabrics including nylon or other fibers such asrayon, wool, acetate or acrylics are generally best tested by the procedure where the ester solution is added first, followed by the dye solution. Unless heating is unduly prolonged or the concentration of ester too low, the color introduced onto the other fiber is fugitive and can be scoured away completely. The dyestuff Anthra'quinone Milling Blue BL is particularly effective when nylon is present; some of the other acid dyes are most difficult to remove and should be avoided. Since nylon, rayon, wool, acetate, and some acrylics are normally acid-dyeable, there is a great risk of staining them per manently when the order of addition of ester and dye is reversed.

Although water is generally the solvent of choice for the dye solution of this invention, it may sometimes advantageously be replaced wholly or in part by one or more highly polar and water-miscible organic solvents. Among the solvents capable of totally replacing water in the dye solutions are the anhydrous alcohols methano], ethylene glycol, diethylene glycol, and propylene glycol. A 50-50 mixture of methanol and glycerol is also effective, although glycerol by itself is apparently too viscous to perform satisfactorily. Ethanol, higher alcohols, and the organic amide solvents such as dimethylformamide, dimethylacetamide, N- methylpyrrolidone, hexamethylphosphoramide, and the like are apparently too organic in nature to provide the desired color patterning when water is absent. These more organic solvents, as well as methanol and the polyols, when diluted to substantial degrees with water, generally are as effective in the invention as water alone. There seem, in fact, to be combinations where the speed of development and the visual sharpness of the patterning are increased by the presence of the organic liquids as co-solvents with water. Although it is within the ordinary skill of the art to test various combinations of polar solvents in association with various dyes and esters, without departing from the scope of the invention, it should be recognized that not all combinations are equal in performance. Untried systems should, therefore, be tested on a small scale before complete reliance is put in them. A wide variety of typical effective solventand dye combinations, as well as some of the complications which may arise, are shown in the examples hereinafter.

The mechanism controlling this invention is not fully understood and therefore it is not desired that this invention should be limited by the following speculations on it. These comments are based on water as the dye solvent, but they are believed applicable, in principle,

to its alcohol and mixed-solvent substitutes. Underlying these speculations is the need to explain the wholly unanticipated discovery that an ester causes a preferential attraction between an acid dye and the surface of a basic-dyeable fiber, this preference apparently existing only in the presence of the ester. This attraction manifests itself in a variety of forms. It comes into play no matter what the order of addition of ester and dye. Even at the time where the solutions have just been applied and evaporation of ester solvent and water has hardly begun, traces of the patterning of disperseand basic-dyeable polyester fibers sometimes begin to emerge. As the solvent and water evaporate, the residual dye appears to concentrate on the basic-dyeable yarns. If the two yarns are woven or knitted to form a pattern, the pattern shows the basic-dyeable fibers as dark and the disperse-dyeable fibers as lighter zones. The exact pattern observed is considerably dependent upon the form and composition of the fabric, apparently being influenced somewhat by the ease of migration of dye solution from one yarn to the other. If threads of either fiber have unintentionally been included in a supply of the other, light or dark lines appear in the otherwise uniformly stained fabric. In any case the result is a shaded fabric where the shades range from dark to light depending roughly on the location of each type of component yarn.

It has been observed that water or one of its aforementioned polar substitutes apparently must be present if this invention is to work. Also present is a fiber containing strongly polar groups (sulfonic groups being believed present in commercially-available basic-dyeable polyesters). It is believed that the polar solvent present acts as a bridge capable of dissolving and thereby connecting two mutually repulsive groups: the sulfonic groups of the fiber and the sulfonic groups, or more generally the water-solubilizing groups, of the dye.

The role of the ester is more difficult to visualize. It is believed to be an agent capable of wetting polyester and other fibers, but evidently also capable of leaving sulfonic groups-exposed to direct contact with water and through it, with dye. When the water starts to dry up it appears reasonable that the ester, spread out over both types of polyester fibers but leaving the sulfonic groups relatively exposed, would encourage the concentrating of water (and dye dissolved in it) at the sites most attractive to it. Excessive amounts of ester apparently swamp and cover up even the sulfonic groups. The solutions of dyes in glycols, presumably because of being far less volatile than their aqueous counterparts, require longer exposure to heat to develop the color pattern.

This mechanism also explains the observation herein that certain dyes outside the classes generally regarded as acid or acidic dyes also fall within the scope of the process of this invention. Some of these dyes are watersolubilized by inclusion of groups such as polyethoxyethanol and are ordinarily more likely to be used as fugitive tints than as permanent dyes. Dyes of this class have been found especially effective when identifying blends containing wool, this fiber being subject to permanent staining with some of the other dyes which perform well in the absence of wool. Typical of these polyethoxylated dyes are the sometimes non-sulfonated tints described in the American Dyestuff Reporter, 55, No. 21, 100-103 (i966), and used as non-selective fugitive tints for a variety of fibers. It has also been found that certain dyes of the class of reactive dyes do not react with polyester fibers under the mild conditions of the test herein and therefore do not become pennanently fixed. The variety of dyes within this class is constantly growing.

S complex is the field of available dyes that the precise delineation of those applicable in the present process is essentially impossible. Kirk-Othmers Encyclopedia of Chemical Technology, 2nd Edition, Volume 7, pages 476-7 and others, illustrates the tremendous overlap in dye classes. For example, acid dyes are listed as azo (including premetallized), anthraquinone, triphenylmethane, azine, xanthene, nitro, and nitroso. Reactive dyes are azo, anthraquinone, phthalocyanine, and stilbene. Sulfonated members of virtually all classes are shown in the tables of pages 472-75. Reactive dyes containing polyethoxyethyl solubilizing groups are not difficult to envision.

In situations where the presence of a visible stain may be objectionable, selected fluorescent optical brighteners, invisible except under ultraviolet light, may be employed in the invention. Short-wavelength UV is most effective. Optical brighteners are particularly useful in identifying cones of yarn, especially when it may not be convenient to scour off the brightener until a later time. The procedure followed is essentially the same as with a visible dye, except that the differences in the yarns, or fabrics made from them, are observed as a bright yellow-white fluorescence on basic-dyeable polyester, contrasted with a barely visible fluorescence on regular polyester. It is obvious that the yarns must not have been treated with optical brighteners during manufacture, since these would interfere with the test. In tests on fabrics, cautious use of the heat gun, less than that usually preferred with visible dyes, appears to be needed. On the other hand, in tests on cones of yarn the fluorescence was found to develop readily without application of heat.

Esters such as glyceryl triacetate, diethyl maleate, and diethyl succinate, all of which have proved generally suitable for use with goods to be heat-set before scouring, as is disclosed in greater detail hereinafter, have proved effective in conjunction with the optical brighteners. It is believed that a much broader range of esters may be used when scouring precedes heatsetting.

Optical brighteners applicable in the invention include Leucophor BS (C.l. Fluorescent Brightener 49), Leucophor BSB (both from Sandoz Colors and Chemicals), lntrawite CF Liquid (from lntracolor Corp), all being acidic brighteners, and others.

Fluorescent brightener levels of 0.5 to 1.0 percent in water seem to be optimal, higher levels tending to produce a light yellow stain in visible light. The addition of ammonium hydroxide to the aqueous brightener to a pH of 9-10 enhances the fluorescence contrast between the disperse-dyeable and basic-dyeable polyester.

The present invention is not believed to be dependent on the dye used. Each dye appears to be but one of a wide range of agents acting under the influence of an ester, and it is believed that the latter is at the heart of the invention. The dyestuff utilized may be generalized in terms of its properties: water soluble; fugitive in the presence of a polyester and especially a sulfonated polyester, consequently not a cationic dye; most commonly of the class of acid dyes, which includes simple acid dyes, premetallized acid dyes, and most direct dyes; may be of the class of reactive dyes, if watersolubilized and so chosen as not to be reactive with the fibers present under the conditions of the test. One skilled in the art, building on the teaching of this invention, can utilize a wide range of dyes without further invention and without being outside its scope.

The most critical and distinctive element in this invention is the use of an ester, at concentrations of l-l00 percent in inert solvents, 10-20 percent being generally preferred. Although a number of other types of compounds have been evaluated, only esters have been found effective. The range of useful esters seems almost unlimited, but a high-boiling (above about 150C) and substantially water-insoluble ester is usually preferred. Volatile esters such as ethyl acetate and amyl acetate give fleeting differentiations between the basic-dyeable and disperse-dyeable polyesters, but the shade differences last only until the esters have evaporated. Where volatile esters are used, the test works best when the concentration of ester in solvent is increased markedly, to even as high as percent.

No esters have been found which did not give a readable differentiation of the polyester yarns at some level of ester concentration. The most consistently effective esters have generally been those derived from higher aliphatic alcohols, butanol and above, when combined with acids giving esters boiling above about C. An exception, however, is the preference, discussed in greater detail hereinafter, for esters of lower alcohols when heat-setting precedes scouring, or when fibers such as nylon or wool are present.

A generally preferred and highly effective ester solution, at least when scouring precedes heat-setting, is a 9 10 percent solution of di-Z-ethylhexyl phthalate in perchloroethylene.

Other esters found effective are diethyl phthalate, dibutyl phthalate, diisooctyl adipate, dibutyl sebacate, glyceryl triacetate, tricresyl phosphate, trioctyl phosphate, triethyl phosphate, epoxidized soybean oil, triethylene glycol di-2-ethylhexoate, vegetable oil esters such as Wesson oil and cottonseed oil, dioctyl maleate, phenyl acetate, benzyl benzoate, and liquid polyesters such as polyethylene adipate and polycaprolactone.

It is usually desirable to dissolve the ester in an inert diluent, the nature of which is not believed critical. Preferably, however, it should be lower-boiling than the ester chosen. Water-soluble solvents such as acetone and methanol have been found effective, with proper choice of dye and dye solvent, but the shade contrasts are not so sharp as with the preferred waterimmiscible solvents such as benzene, toluene, and perchloroethylene. Other effective solvents are carbon tetrachloride, ethyl ether, xylene, and pyridine. The purpose of the diluent is to permit application ofeach ester in the concentration best suited to it, the concentration being easily established by a few simple experiments on patterned test fabrics. Too little ester gives inadequate color contrast, while too much, especially with the more-effective esters, appears to obliterate the test by essentially swamping the basic-dyeable fiber which normally carries the color.

A wide range of acid dyes are believed effective in this invention. These are applied as aqueous solutions, at concentrations varying with their dyeing strength and color. A two-percent aqueous solution of Anthraquinone Milling Blue BL, Acid Dye Number l22,is particularly effective. The use of other dyes is detailed in the examples.

After application of ester and dye solutions, heat may and usually preferably is applied, to hasten and often to sharpen the contrasting shades of .color, as well as to dry the test specimens. Heatmay be applied by any known means, such as blowing with room temperature air or drying in an oven. However, a portable hot air gun, heat gun or dryer has been found to be the most effective and convenient means for performing this step. For preparation of test samples according to this invention, there was used a so-called heat gun or dryer obtained from Scientific Products Division of American Hospital Supply Corporation, Evanston, lllinois 60201, Dryer Model D 8010-1 (nozzle length 3 inches, 1 volts, 60 cycles, 5 ampere rating, temperature range 200300F).

For preparation of' samples, strips of test fabrics are conveniently mounted in a vertical position between two vertical metal rods in a fume hood, treated with the test solutions, and dried with the heat gun or dryer until the color pattern emerges, and until dry to the touch if handling is required. However, heating to dry should not be continued to the point of setting the color into the fabric. Hence, a'dryer with air heater capacity in the indicated range of 200 300F is preferred.

Accordingly, color contrast is generally better with application of low to moderate heat, but this is not always true. Triethyl phosphate, for instance, is clearly more effective if left unheated. In fact, heat quickly destroys its contrast.

Although the invention is most broadly applicable, in terms of variety of esters, solvents, and operating conditions, to distinguishing between disperseand basicdyeable polyesters in the absence of other'fibers, the method may also be adapted to more complex mixtures. The most common problem to be overcome is the tendency of the other fibers to be permanently stained by the test dyes. Particularly when fibers such as nylon and wool are present, both of these being by nature substantive to acid dyes, it is believed preferable, except when using the hereinbefore mentioned polyethoxylated tints, to scour the test materials thoroughly before heat-setting.

When nylon is present it is possible to retain fugitivity of color even when using some of the acid dyes, but in general the scouring requirements are too rigorous to make such dyes as attractive as others for this purpose. With nylon-containing textile materials, the polyethoxylated tints, used in conjunction with esters of polyols or lower alcohols, such as glyceryl triacetate or diethyl succinate, afford much the greater freedom of action and are thus preferred. Nonetheless, that a more general choice of dyes is possible is verified by the fact that C.l. Direct Blue 15 (C.l. 24400), when applied in conjunction with 25 percent dioctyl phthalate in perchloroethylene, produces a clear three-component test pattern which washes out readily with mild soap. Even C.l. Acid Blue 122 may be used without loss of fugitivity, provided care is taken to heat no longer than required for the shade differences to appear. In a three-fiber combination, the nylon stains most deeply, basicdyeable polyester next, and disperse-dyeable polyester least.

The choice of agents and conditions for fugitive testing for the polyesters in the presence of wool is more restricted. Here it appears that the ethoxylated tints in conjunction with esters such as glyceryl triacetate and diethyl succinate are preferred. Limitations on the use of higher esters, which are otherwise effective, seem to be imposed primarily by their lesser ease of scouring.

One of ordinary skill will readily be able to apply the teachings of this invention to other combinations and structures of yarns and fibers where the differences in fiber staining are sufficient for visual detection.

It has been observed that, in general, the greater the amount of ester applied to the test specimens, the better the fugitivity of color from them in scouring, this being particularly evident when extra fibers such as nylon and wool are present. Aqueous dye concentrations of 0.5-2.0 percent give adequate contrasts, in either the presence or absence of additional fibers, the lower concentrations being generally preferred in multifiber combinations.

Prior pastel staining of the component yarns with conventional tints, if such is deemed desirable for some reason, does not appear to interfere with this invention. Neither does the presence of ordinary amounts of knitting oils, especially when an effective combination such as di-2-ethylhexyl phthalate in perchloroethylene is used. In general, however, less possibility of interference will exist if the test method is applied at a point prior to application of oils. Adaptation of the teaching of this invention to the wide variety of specific conditions encountered in mill operations will not be difficult to one of normal skill.

When it is desirable to test yarn or fabric which is later to be heat-set, it is generally preferable to scour the test stain away before the heat-setting. Otherwise, the 350-400F temperatures nonnally applied may set the acid dye so firmly that fugitivity is lost. Careful choice of dye and ester, however, generally makes it possible to heat-set the stained yarn or fabric in the greige, without loss of color fugitivity.

Dyes such as C.l. Acid Blue 74 (CI. 73015), C.l. Acid Green 3 (CI. 42085), C.l. Acid Yellow 3 (CI. 15985), and Cl Acid Yellow 17 (CI. 18965), although their original test patterns are less clearly defined than those of the preferred C.l. Acid Blue 122, may be more easily scoured away after heat setting.

When the generally preferred di-Z-ethylhexyl phthalate and others of the higher molecular weight esters are used and not scoured away before heat-setting, subsequent regular dyeing may produce a darker color in the test area than in its surroundings. This defect may be avoided by the use of esters of lower alcohols or of polyols, such as ethyl acetate, amyl acetate, ethyl benzoate, diethyl succinate, diethyl maleate, glyceryl triacetate, ethylene diacetate, and the like. The preferred esters are those boiling over about 150C, since, as noted hereinbefore, those with lower boiling points tend to evaporate too fast and give only fleetingly visible test patterns.

These problems are specific to heat-set goods and do not arise when scouring precedes heat-setting.

Components may be applied by brush, pressurized spray, roller, pad bath, or in any other convenient manner. The most generally satisfactory method, particularly where treatment of only a limited area is desired, is by a combination of brush and spray as detailed in the examples.

It is presently visualized that the treating components according to the invention can be assembled into kit form, permitting ease of transportation, use and storage, with a container for the dyestuff, and a container for the ester Both containers may be joined together, and is desired, attached to the heat gun. Either or both containers may be of the aerosol-pressurized type. Alternatively, the dyestuff or ester container, or both, may be equipped with pad, swab, brush, or atomizer type applicator means. In a highly sophisticated approach, both containers may be of the aerosol or atomizer type, and be connected to the heat gun to permit essentially single handed operation with programmed or manual control as desired.

For removal of the stains introduced onto the fabrics a two-part scouring procedure is preferred. Residual ester is removed by passing the fabric or yarn through an organic solvent such as perchloroethylene, followed by drying and then rinsing with water. Scouring may also be achieved in one step by aqueous detergent systems well known in the textile art.

Other details of the invention are'shown in the following examples which illustrate some of the novel features hereof.

Example 1 A woven test fabric composed of bands of Type 54 disperse-dyeable and Type 64 basic-dyeable Dacron polyester was sprayed with triethylene glycol di-2- ethylhexoate and then oversprayed with 2 percent aqueous Anthraquinone Milling Blue BL, C.l. Acid Blue 122 (Colour lndex, 2nd Edition, Volume 1, 1956). After standing overnight both fibers were blue, the Dacron 64 being much the darker. Similar results were obtained with separate Type 54 and 64 swatches in the same test.

Example 2 A knitted fabric with bands of Type 56 dispersedyeable and Type 92 basic-dyeable Dacron was sprayed with triethylene glycol di-Z-ethylhexoate, heated for 2 minutes with the heat gun, sprayed with 2 percent aqueous C.I. Acid Blue 122, and let air dry, The Type 92 Dacron was heavily stained, the Type 56 only slightly. When the fabric was sprayed with the dye without ester pretreatment, no distinction between the fibers was apparent.

Example 3 Disperse-dyeable Type 56 Dacron and basic-dyeable Type 92 Dacron polyesters were double-knit into a plaid fabric in which the frontal squares were Type 56 and the entire back of the fabric wholly and the frontal cross-hatch bands predominantly Type 92. Swatches of the undyed fabric were used as test samples in this and Examples 4-17 which follow.

A swatch of the Types 56/92 Dacron double-knit fabric was treated on the left with percent and on the right with 50 percent solution (in perchloroethylene) of triethylene glycol di-2-ethylhexoate and then oversprayed with 2 percent aqueous C.l. Acid Blue 122. Both'halves of the fabric developed a differentiation pattern in less than one minute of heating with the heat gun, the contrast being sharper with the 50 percent solution. (The patterns referred to in this example and those following always show the Type 92 as deep blue and Type 56 as light blue to near-white.)

Example 4 The patterned fabric of Example 3 was dipped into a 10 percent solution of triethylene glycol di-2- ethylhexoate, then sprayed with 2 percent aqueous C.l. Acid Blue 122 and heated with the heat gun. The sharply differentiated pattern developed quickly, the Type 92 Dacron being dark blue and the Type 56 light blue. The same procedure, but with the ester omitted, produced no pattern.

Example 5 A swatch of the test fabric of Example 3 was brushed with 2 percent aqueous C.I. Acid Blue 122, allowed to stand for about one minute and then oversprayed with 10 percent di-2-ethylhexyl phthalate solution in perchloroethylene. Less immediate pattern development occurred than is observed in Example 7 below, but the heat gun quickly brought forth a clear pattern, indicating that reversing the order of ester and dye application did not adversely affect the test.

Example 6 Triethylphosphate was sprayed and painted at 100 percent concentration onto the knitted fabric of Example 3, but no pattern at all was produced on dye overspraying. Painting on at 10 percent concentration in perchloroethylene, followed by overspray with Cl. Acid Blue 122, quickly produced a clear pattern, which persisted for several minutes so long as the heat gun was not used, and gradually faded away in about 15 minutes. At 20 percent perchloroethylene, the pattern was even clearer. Here too the heat gun quickly destroyed the pattern. It was apparent that this ester was different from most of the others tested in its speed of pattern development at room temperature and its adverse reaction to application of heat.

Example 7 A 10 percent solution of each of the following esters in perchloroethylene was painted with a brush onto swatches of the test fabric of Example 3: di-2- ethylhexyl phthalate, tri-2'ethylhexyl phosphate, and epoxidized soybean oil. The wet areas were allowed to stand for about one minute and then were oversprayed with 2 percent aqueous C.l. Acid Blue 122 and heated with the heat gun, developing sharp patterns in all of the swatches. After extraction with perchloroethylene, all lost their blue color on rinsing with cold water. Heating in an oven gave the same results with di-2- ethylhexyl phthalate as using the heat gun. The practice of letting the samples'stand for about one minute before overspraying was adopted in the subsequent examples.

Example 8 Substitution of toluene, xylene, and pyridine for perchloroethylene in 10 percent solutions 'of tri-2- ethylhexyl phosphate, using the procedure of Example 7, gave the same differentiations of shade as before.

Example 9 When methanol and acetone, both completely watermiscible, were substituted for perchloroethylene in 10 percent solutions of tri-Z-ethylhexyl phosphate in the procedure of Example 7, sharp patterns indistinguishable from those of the earlier example were obtained.

Example 10 and amyl acetate.

Example 11 In tests at the 10 percent level using the procedure of Example 7, excellent shade differentiations were achieved with solutions of diisooctyl phthalate, dibutyl sebacate, tricresyl phosphate, di-Z-ethylhexyl maleate, and polycaprolactone of molecular weight 1850. It is evident that low levels of a wide variety of high-boiling esters are effective in this invention.

Example 12 At the 10 percent level, with the procedure of Example 7, dimethyl phthalate left an ill-defined pattern after drying with the heat gun. Diethyl phthalate was somewhat better. When the concentration of each ester was raised to 20 percent, sharply defined separation patterns emerged under the heat gun.

Example 13' Glyceryl triacetate, at the 10 percent level in the procedure of Example 7, gave an inferior pattern which became sharply defined with increase in ester level to 20 percent.

Example 14 Cottonseed oil and Wesson oil (a mixture of cottonseed and soybean oil) gave sharply defined patterns at the 20 percent level in the procedure of Example 7. At 10 percent the patterns were still evident, but less sharp than at 20 percent.

Example 15 Benzyl benzoate gave only a fair separation in the procedure of Example 7 at the 20 percent level, but at percent it produced a sharply defined shade differ ence.

Example 16 Six other acid dyes were evaluated on the knit test fabric by the procedure of Example 7. These were C.l. Acid Yellow 17 (CI. 18965) and Cl. Acid Violet 7 (CI. 18055), monoazo dyes; C.1. Acid Yellow 73 (C.l. 45350) and CI. Acid Red 52 (CI. 45100), xanthene dyes; C.l. Acid Blue 25 (CI. 62055), an anthraquinone dye; and Cl. Acid Blue 83 (CI. 42660), a triphenylmethane dye. Their aqueous solutions gave excellent separation patterns, completely fugitive when the test samples were scoured.

Example 17 The procedure of Example 7 was modified in that the di-2-ethylhexyl phthalate and dye solutions were sprayed simultaneously onto the test fabric from twin nozzles. No difference could be seen in the contrast pattern from those of Examples 5 and 7.

Example 18 The procedure of Example 7 was modified in that the C1 Acid Blue 122 was sprayed as a 1 percent solution in ethylene glycol instead of water. Although the pattern developed more slowly under the heat gun, it came out sharp and clear. Similar results were obtained with propylene glycol and diethylene glycol. Examples 18-21 use 25 percent di-2-ethy1hexyl phthalate in perchloroethylene as the ester solution.

Example 19 When the water of Example 7 was completely substituted by methanol (1 percent CI. Acid Blue 122 solution in methanol), the pattern developed faster than in Example 18, but was less distinct. When a 1 percent Acid Blue 122 solution in 50-50 methanol-water was used instead,'the pattern began to develop rapidly even before heat was applied, and was sharper than that obtained with a purely aqueous control solution.

Example 20 Total replacement of the water of Example 7 with ethanol (1 percent Acid Blue 122 solution) prevented development of the test pattern, but when a 50-50 ethanol-water solution was used, the results were the same as with the 50-50 methanol-water solution of Example 19.

Example 21 When the water in Example 7 was replaced with either dimethylformamide or dimethylacetamide, no test pattern developed on heating. When the 1 percent solution of Acid Blue 122 was made up in 50-50 dimethylformamide-water, the early pattern not only was as sharp as with the wholly aqueous dye, but was even more pronounced because the stain from this medium was darker blue than the slightly reddish-blue of the aqueous dye. With 50-50 dimethylacetamide-water the pattern was not sharp, but at 25-75 dimethylacetamide-water proportions the pattern was excellent. It was noted, however, that when heating was continued for 45 seconds or longer the pattern began to become somewhat smeared, and color removal by scouring became less efficient. Hexamethylphosphoramide and N- methylpyrrolidone behaved substantially like dimethylacetamide when tested in the same manner and at the same concentrations as the latter. The complications with all four of these amides were judged to arise from their low volatility and their high miscibility with the ester phase when drying and water removal were carried too far.

Example 22 Yarn cones were prepared by winding lengths of Type 54 and Type 64 Dacron onto each cone so that the yarns lay in separate bands across the radius. A percent solution of triethylene glycol di-2-ethylhexoate was painted with a brush across the top of the cone and then oversprayed with aqueous C.l. Acid Blue 122. The bands of Type 64 Dacron were distinctly deeper blue than the Type 54 bands.

Example 23 A cone like that of Example 22 was brushed on its end with 2 percent CI. Acid Blue 122, allowed to stand for about one minute, sprayed with a 25 percent solution of di-2-ethylhexyl phthalate in perchloroethylene, and heated with the heat gun. Clearly darker blue bands showed the location of the basic-dyeable Type 64 Dacron. Results were the same when the dye was sprayed and the ester brushed on. The zones were more distinct than when the ester solution was added first.

Example 24 A test sock was knitted in zones of six commercial disperse-dyeable polyester yarns in such a way that a thread of DuPont Type 92 Dacron and another of Fiber Industries Type 764 Fortrel basic-dyeable polyesters ran through each zone. The samples were sprayed with 10 percent di-2-ethylhexyl phthalate in perchloroethylene, allowed to stand about one minute, and then sprayed with 2 percent aqueous C.l. Acid Blue 122, followed by heating with the heat gun. This produced deep blue lines running through all of the zones and clearly showed the two basic-dyeable threads.

Example 25 Lengths of yarn of Type 54 and Type 64 Dacron were dipped into a l() percent solution of di-2-ethylhexyl phthalate in perchloroethylene, allowed to drain briefly, sprayed with a 2 percent solution of Cl. Acid Blue 122, and dried with the heat gun. Although the contrast in shade was not so pronounced as on fabrics, the Type 64 yarn was distinctly darker blue.

Example 26 A creel was loaded with bobbins of disperse-dyeable Type 54 Dacron, with several bobbins of basic-dyeable Type 64 scattered among them at intervals. After the warp was established, the warper was stopped and a band of 10 percent di-Z-ethylhexyl phthalate in perchloroethylene. was painted across the open warp and oversprayed with 2 percent aqueous C.l. Acid Blue 122. Playing the heat gun over the treated band brought the deeper blue of all of the Dacron 64 threadlines clearly into view.

Example 27 Disperse-dyeable Type 56 Dacron and basic-dyeable Type 92 Dacron polyesters were plied together into yarn. (Such yarn, when knitted and cross-dyed, normally produces a heather effect.) The yarn was doubleknitted, and a swatch of the fabric was treated with di- 2-ethylhexyl phthalate and 2 percent aqueous C .l. Acid Blue 122 by the method of Example 7. Since the Type 92 Dacron component was so much the darker, a fugitive heather effect was pronounced as if the fabric had been cross-dyed.

Example 28 This example clearly exhibits the superiority of this invention over the conventional fiber-tinting process of the art. A supply of basic-dyeable Type 92 Dacron polyester yarn was conventionally tinted blue before being knitted with colorless disperse-dyeable Type 56 Dacron into a 50-50 blend. It was only by careful scrutiny that one could see the pattern of blue fibers running diagonally in one direction, and of white fibers running normal to them. When a section of this fabric was brushed with a 10 percent solution of a di-2- ethylhexyl phthalate, sprayed with 2 percent CI. Acid Blue 122, and heated with the gun, the contrast in the pattern was drastically accented, such that the intersecting blue and white lines, plus other detail completely undefined by the original tint, came clearly into view. The contrast was as sharp as if the Type 92 Dacron had been permanently and deeply dyed with a basic blue, yet with no loss of fugitivity.

Example 29 Three dyes carrying Colour Index classifications other than of acid dyes were evaluated by the procedure of Example 7, using di-Z-ethylhexyl phthalate as the ester, in perchloroethylene. The dyes, as 1 percent aqueous solutions, were C.l. Direct Blue 15 (CI. 24400), C.I. Reactive Red ll, and Cl. Reactive Blue 2 1. With all three dyes, differentiations of the disperseand basic-dyeable fibers in the test fabrics were weak when 10 percent ester solutions were used. When the ester concentrations were raised to 25 percent, sharp patterns resulted.

Example 30 This example demonstrates the utility of the aforementioned class of tints solubilized by the inclusion of polyethoxyethanol groups. Versatint Blue LF (Sylvan Chemical Company), a triphenylmethane-based tint of this class, diluted 1:100 and sprayed onto fabric pretreated with 25 percent di-2-ethylhexyl phthalate, the procedure being otherwise that of Example 7, produced a sharply defined color contrast pattern. Fugitivity on scouring was complete. Versatints Red P3 and Yellow P4 also gave clear patterns, but the contrasts were not so great as with the blue.

Example 31 This example shows the effect of using a combination of an ester and a dye which avoids both oil and dye staining when heat-setting precedes scouring. About one-fifth of the area of a swatch of the double-knit test fabric of Example 3 was brushed with a 25 percent solution of glyceryl triacetate in perchloroethylene. After 30 seconds the treated area was oversprayed with a 0.5 percent aqueous solution of Cl. Acid Blue 74 and heated with the heat gun to develop a clear test pattern.

Example 32 The procedure of Example 31 was repeated except that a 25 percent solution of diethyl succinate'was substituted for the glyceryl triacetate. A clear test pattern and absence of after-staining were observed;

Example 33' This example and Example 34 demonstrate the use of optical brighteners as substitutes for the visible dyes of the other examples. The knit test fabricof Example 3 was brushed with a 25 percent solution of diethyl succinate in trichloroethylene. After 30 secondsthe sample was sprayed with a solution of 4 g. of lntrawite CF Liquid in l ml of water and heated with the heat gun. Under the UV lamp the Type 92 yarn fluoresced strongly while the Type 6 did not. Similar results were obtained with l g/ 100 ml of the lntrawite CF Liquid. Both fabric samples not only lost their fluorescence when subsequently heat set and rinsed with water, but they also dyed (with EastmanYellow 2R (0.25 percent)) clearly and smoothly, with no dark areas or streaks from ester staining.

Example 34 Type 54/92 Dacron yarn cones like those of Example 22 were treatedon their ends with percent solutions of diethyl succinate in trichloroethylene, followed by spraying with Leucophore BSB, diluted 1:100 with water. No contrast appeared at first, but after 15-30 minutes (no heating) the Type 92 yarn fluoresced brightly, while the Type 54 did not. Yarn wound off, heat-set for 3 minutes at 400F, and scoured with water at 140F lost its fluorescence completely. When the pH of the Leucophore BSB solution was raised to 9.6 with ammonium hydroxide,the contrast between the yarns was heightened noticeably.

Example 35 A knit fabric like that of Example 3, but with a separate line of nylon 66 yarn in its pattern, was brushed with a 25 percent solution of di-2-ethylhexyl phthalate in perchloroethylene and then sprayed with 0.5 percent aqueous Direct Blue 15 (CI. 24400). Cautious application of heat produced a three-tone color pattern in which the nylon was the darkest, the Type 92 Dacron next, and the Type 56 Dacron much the lightest. Unless the heating was unduly prolonged, the color came out of the fabric on washing with mild soap. Longer heating tended to set the color permanently in the nylon.

When the same test conditions were applied to a test fabric in which wool was substituted for the nylon, a similar dark line pointed out the wool. Color washed out readily with mild soap. When the concentration of ester was reduced from 25 percent to 10 percent, neither the color contrast nor the ease of scouring was as good as before. Although removable in the laboratory, this dye was not judged optimum for use with ordinary production scours.

Example 36 The nylon-containing test fabric of Example 35 was brushed with a 25 percent solution of glyceryl triacetate in perchloroethylene and then sprayed with 0.5 percent aqueous C.I. Acid Blue 74, followed by heating to bring out the three-shade pattern, nylon being much the darkest yarn. Color was fugitive on scouring. Even C.l. Acid Blue 122 in conjunction with dioctyl phthalate was effective with this three-fiber blend, but the chance of permanently staining the nylon by slightly excessive heating was judged to be too great to make this dye especially attractive.

Example 37 Example 38 A three-yam blend fabric containing wool, wool/Dacron 64-and Dacron 54 was brushed with 25 percent glyceryl triacetate in perchloroethylene, oversprayed with full-strength Versatint Blue LF, and heated to develop a color pattern. The contrast between wool and wool/Dacron 64 was too little to see, but these yarns were much darker than the Dacron 54. The color readily washed out of all of the yarns on scouring. Syltint Blue, also made by Sylvan Chemical Co. and of the same class of dyes as the Versatints but with shorter polyethoxyethanol groups, was applied full strength in the same manner and found to give sharper contrast of pattern, also readily fugitive.

Example 39 A 25 percent solution of diethyl succinate in perchloroethylene was brushed onto the wool blend fabric of Example 38 and heat was applied to evaporate the solvent. Syltint Blue, full-strength, was then sprayed on. Additional heat to dry the fabric produced a sharp pattern, permanent until scoured.

Example 40 A test fabric was knitted from yarns made from 65/35 dacron 92/rayon and 65/35 Dacron 54/rayon. The procedure of Example 7, using di-2-ethylhexyl phthalate at the 10 percent level, produced a test pattern with nearly normal shade contrast, slightly diminished by the uptake of dye by the rayon in both yarns.

The invention is defined in the following claims wherein:

What I claim is:

l. A fugitive-staining process for identifying whether basic-dyeable synthetic fibers are present among or apart from non-basic dyeable fibers, said process comprising treating said fibers with a fugitive coloring agent in the presence of a liquid organic ester so that the coloring agent is preferentially attracted to the surface of the basic-dyeable synthetic fibers thereby preferentially staining said basic dyeable synthetic fibers.

2. The process of claim 1 wherein the coloring agent is non-cationic fugitive dye or optical brightening agent.

3. The process of claim 1 wherein the basic-dyeable synthetic fibers are basic-dyeable polyester fibers present with disperse-dyeable polyester fibers.

4. The process of claim 3 wherein the coloring agent is applied as a solution in a solvent selected from the group consisting of water, alcohols and mixtures thereof.

5. The process of claim 4 wherein the ester has a boiling point above about 150C.

6. The process of claim 4 wherein the alcohol is selected from the group consisting of methanol, ethylene glycol, diethylene glycol, propylene glycol and mixtures of methanol and glycerol.

7. A fugitive-staining process for distinguishing a basic-dyeable polyester textile article from a dispersedyeable polyester textile article comprising treating said article with a liquid organic ester and an aqueous solution of water-soluble, non-cationic fugitive dye which preferentially stains the basic dyeable article.

8. A process according to claim 7 wherein said ester is selected from the group consisting of di-Z-ethylhexyl phthalate, diethyl phthalate, dibutyl phthalate, diisooctyl adipate, dibutyl sebacate, glyceryl triacetate, tricresyl phosphate, trioctyl phosphate, triethyl phosphatc, epoxidized soybean oil, triethylene glycol di-2- ethylhexoate, vegetable oil esters, dioctyl maleate, phenyl acetate, benzyl benzoate, polyethylene adipate and polycaprolactone.

9. A process according to claim 8 wherein said treatment involves applying said ester and an aqueous solution of the dye to said articles and thereafter heating to develop a color contrast between said articles.

10. The process of claim 7 wherein the ester is dissolved in a volatile inert organic diluent.

11. The process of claim 10 wherein the diluent is substantially water-immiscible.

12. The process of claim 10 wherein the ester has a boiling point above about 150C.

13. The process of claim 7 wherein at least one article is a fiber.

14. The process of claim 7 wherein at least one article is a yam.

15. The process of claim 7 wherein the article is a fabric.

16. The process of claim 15 wherein the fabric contains mixed fibers and or yarns of basic-dyeable polyester and disperse-dyeable polyester.

17. The process of claim 15 wherein the fabric is woven, knit or nonwoven.

18. The product of claim 7.

19. A textile identification procedure for distinguishing at least one basic-dyeable polyester textile article from at least one disperse-dyeable polyester textile article in a product containing intentional or inadvertent mixtures or combinations of at least one basic-dyeable polyester textile article and at least one dispersedyeable polyester textile article comprising treating said product with a liquid organic ester and an acid dye solution which preferentially fugitively stains the basicdyeable article.

20. The procedure of claim 19 wherein the treatment is carried out in the presence of water.

21. The procedure of claim 19 wherein the ester is dissolved in a water immiscible solvent.

22. The procedure of claim 19 wherein the treated article is then heated.

23. The treated product of claim 19.

24. A fugitive-staining process for distinguishing a basic-dyeable polyester textile article from a dispersedyeable polyester textile article combined therewith comprising treating said articles together with (l) a volatile, substantially inert, substantially waterimmiscible organic solvent solution of a liquid organic ester boiling above about C and (2) with an aqueous solution of an acidic dye, thereby preferentially staining the basic dyeable article.

25. The process of claim 24 including the further step of heating the articles after said treatment.

26. A fugitive, preferential, identification process for a basic-dyeable polyester textile article comprising treating said article with a water immiscible solvent solution of a liquid organic ester boiling above about 150C and an aqueous solution of an acidic dye.

27. The process of claim 26 including the further step of heating the treated article at below the heat setting temperature to effect volatilizing of said solutions, and essentially dry said treated article.

28. The process of claim 26 including the further step of rinsing or scouring said treated article. 

2. The process of claim 1 wherein the coloring agent is non-cationic fugitive dye or optical brightening agent.
 3. The process of claim 1 wherein the basic-dyeable synthetic fibers are basic-dyeable polyester fibers present with disperse-dyeable polyester fibers.
 4. The process of claim 3 wherein the coloring agent is applied as a solution in a solvent selected from the group consisting of water, alcohols and mixtures thereof.
 5. The process of claim 4 wherein the ester has a boiling point above about 150*C.
 6. The process of claim 4 wherein the alcohol is selected from the group consisting of methanol, ethylene glycol, diethylene glycol, propylene glycol and mixtures of methanol and glycerol.
 7. A fugitive-staining process for distinguishing a basic-dyeable polyester textile article from a disperse-dyeable polyester textile article comprising treating said article with a liquid organic ester and an aqueous solution of water-soluble, non-cationic fugitive dye which preferentially stains the basic dyeable article.
 8. A process according to claim 7 wherein said ester is selected from the group consisting of di-2-ethylhexyl phthalate, diethyl phthalate, dibutyl phthalate, diisooctyl adipate, dibutyl sebacate, glyceryl triacetate, tricresyl phosphate, trioctyl pHosphate, triethyl phosphate, epoxidized soybean oil, triethylene glycol di-2-ethylhexoate, vegetable oil esters, dioctyl maleate, phenyl acetate, benzyl benzoate, polyethylene adipate and polycaprolactone.
 9. A process according to claim 8 wherein said treatment involves applying said ester and an aqueous solution of the dye to said articles and thereafter heating to develop a color contrast between said articles.
 10. The process of claim 7 wherein the ester is dissolved in a volatile inert organic diluent.
 11. The process of claim 10 wherein the diluent is substantially water-immiscible.
 12. The process of claim 10 wherein the ester has a boiling point above about 150*C.
 13. The process of claim 7 wherein at least one article is a fiber.
 14. The process of claim 7 wherein at least one article is a yarn.
 15. The process of claim 7 wherein the article is a fabric.
 16. The process of claim 15 wherein the fabric contains mixed fibers and or yarns of basic-dyeable polyester and disperse-dyeable polyester.
 17. The process of claim 15 wherein the fabric is woven, knit or nonwoven.
 18. The product of claim
 7. 19. A textile identification procedure for distinguishing at least one basic-dyeable polyester textile article from at least one disperse-dyeable polyester textile article in a product containing intentional or inadvertent mixtures or combinations of at least one basic-dyeable polyester textile article and at least one disperse-dyeable polyester textile article comprising treating said product with a liquid organic ester and an acid dye solution which preferentially fugitively stains the basic-dyeable article.
 20. The procedure of claim 19 wherein the treatment is carried out in the presence of water.
 21. The procedure of claim 19 wherein the ester is dissolved in a water immiscible solvent.
 22. The procedure of claim 19 wherein the treated article is then heated.
 23. The treated product of claim
 19. 24. A fugitive-staining process for distinguishing a basic-dyeable polyester textile article from a disperse-dyeable polyester textile article combined therewith comprising treating said articles together with (1) a volatile, substantially inert, substantially water-immiscible organic solvent solution of a liquid organic ester boiling above about 150*C and (2) with an aqueous solution of an acidic dye, thereby preferentially staining the basic dyeable article.
 25. The process of claim 24 including the further step of heating the articles after said treatment.
 26. A fugitive, preferential, identification process for a basic-dyeable polyester textile article comprising treating said article with a water immiscible solvent solution of a liquid organic ester boiling above about 150*C and an aqueous solution of an acidic dye.
 27. The process of claim 26 including the further step of heating the treated article at below the heat setting temperature to effect volatilizing of said solutions, and essentially dry said treated article.
 28. The process of claim 26 including the further step of rinsing or scouring said treated article. 